As scientists learn more about COVID-19, it has become clear that the virus especially impacts those with existing medical conditions, such as kidney disease.

Meghan Sise, MD, assistant professor of medicine in the Division of Nephrology, and Kassem Safa, MD, assistant professor of medicine in the Transplant Center and the Division of Nephrology at Massachusetts General Hospital, discuss the impact of COVID-19 on patients who have kidney disease or are transplant recipients, and provide guidance on how to safely get needed care.

How High is the Risk for Contracting COVID-19?

As kidney transplant recipients and those with kidney disease worry about the risk of contracting coronavirus, Dr. Sise and Dr. Safa point out, there is nothing unique about kidney disease that would increase a person’s chance of getting COVID-19. The risk comes from getting necessary care.

“I would emphasize that kidney transplant recipients and patients receiving dialysis shouldn’t be afraid to see their doctor because of COVID-19. It is critical that patients continue receiving the care that they need. Hospitals and other medical settings have taken many steps to ensure patient safety.

Kassem Safa, MD
Associate transplant nephrologist, Mass General's Transplant Center

"Patients on dialysis may be at higher risk for contracting COVID-19 because they cannot self-quarantine at home,” says Dr. Sise. "They need to commute to and from dialysis and interact with the health care system more frequently than most of the population. Fortunately, infection control policies and physical distancing at dialysis units have limited the spread of COVID-19 at these sites."

Dr. Safa agrees. “At this time, there is no evidence to suggest that kidney transplant recipients are at higher risk for contracting COVID-19. Following recommended guidelines will help reduce the risk of coronavirus exposure.”

To reduce risk, patients should:

  • Follow physical distancing guidelines
  • Practice hand hygiene
  • Use face coverings when in public

“I would emphasize that kidney transplant recipients and patients receiving dialysis shouldn’t be afraid to go to their doctor because of COVID-19,” says Dr. Safa. “It is critical that patients continue receiving the care that they need. Hospitals and other medical settings have taken many steps to ensure patient safety. It is important that patients continue to follow their treatment plan and be in contact with their provider with any concerns.”

What is the Risk for COVID-19 Complications?

While kidney disease does not put patients at higher risk of contracting COVID-19, it does put patients at risk for more severe outcomes—such as kidney function decline—during infection.

Though it is not known exactly why patients with kidney disease are more at risk for severe COVID-19, it may be that these patients are typically older and have other chronic illnesses such as diabetes that are risk factors for severe COVID-19. Additionally, these patients may also have a weakened immune system.

Kidney transplant recipients are also at risk for more severe outcomes. “Recipients typically have underlying illnesses that led to having kidney disease at the first place, “says Dr. Safa. “Because of this, they are at higher risk for severe infections. At this time, it is assumed but not entirely proven if the use of immunosuppressant medications to maintain kidney transplant health is a risk factor for worse infections or complications.”

How Does COVID-19 Affect Kidneys?

About one in every three people who are admitted to the hospital for COVID-19 will develop acute kidney injury (AKI)—a sudden decline in kidney function—even if they have never had kidney disease before. This rate of injury increases to more than half for those who become critically ill and need intensive care. In most cases, these patients will require emergency dialysis. 

Though the exact reasons are unclear as to why COVID-19 affects the kidneys, scientists have outlined some possible causes:

  • Kidney structure: One reason why the coronavirus is so contagious is that the spikes in the virus are how the virus attaches to a host cell. SARS-CoV-2, the virus that causes COVID-19, has very sticky spikes that form a strong bond with a receptor called ACE2, which is abundant throughout the human body, including the kidneys. These “crown-like” spikes are what give the coronavirus its name
  • Blood clotting: The purpose of the kidneys is to remove waste and extra fluid from the body. Kidney biopsies from COVID-19 patients have shown that in some instances, tiny blood clots are formed. These blood clots can affect proper kidney functioning
  • Extreme inflammation: Inflammation happens when there is a level of injury to a cell. The body sends different molecules and proteins to that site to improve its healing. However, there are times when the reaction can be extreme, and in these instances, inflammation can damage the immune system response rather than help it

Treatment Options for COVID-19 Patients with Kidney Injury

Current treatment options for COVID-19 patients do not specifically address kidney injury, especially in the beginning.

“In the early phase of infection,” Dr. Sise says, “treatments usually target the virus. Remdesivir is an antiviral drug that was given emergency approval for use in COVID-19."

But she says, "unfortunately, the studies that approved Remdesivir did not include patients with advanced kidney disease or on dialysis. In the later phase of the infection, immunosuppressive treatments such as dexamethasone (a steroid) may be used to prevent the overactive immune response that COVID-19 may trigger. These treatments appear to improve survival, but it is not known if these treatments improve kidney function. Dexamethasone is safe to use in patients with kidney disease. When patients develop severe kidney disease during COVID-19, we use supportive care and dialysis to help them survive.”

The Long-term Effects of COVID-19 on the Kidneys

The long-term effects of COVID-19 on the kidneys are still unknown. “Many nephrologists are concerned that there may be long-term effects on kidney function, that some people with chronic kidney disease may experience a big setback and that some people who did not previously have chronic kidney disease may develop chronic kidney disease,” says Dr. Sise. “However, not enough time has passed to study those effects, and additional research is needed. At Mass General, we’ve begun studying the effect of COVID-19 on kidney outcomes to determine if patients with chronic kidney disease experience long-term kidney complications from COVID-19. We are also a part of a large national registry following kidney transplant recipients who develop COVID-19, designed to study the nature of the disease progression in this special population of patients."